Hydropneumatic control device



E. TOROSSIAN HYDROPNEUMATIC CONTROL DEVICE Dec. 26, 1967 5 Sheets-Sheet 1 F/ l.

Filed Jan. '7, 1966 ZC--r JNVENTOR.

. EDOUARD ToRosS/A/v dm 4. 46156. fn/ay #fra Dec. 26', 1967 E. TOROSSIAN 3,359,728

HYDROPNEUMAT I C CONTROL DEVI CE Filed Jan. 7, 1966 3 Sheets-Sheet 2 INVENTOR.

500ml/2070x055 /n/v Dec. 26, 1967 E. ToRosslAN 3,359,728

HYDROPNEUMATIC CONTROL DEVICE Filed Jan.l '7,1966 5 sheets-sheet s 'f\ mmssww IN VEN TOR.

-Eoun Rn Toaoss/mv BY WA'. j A.

AffaA/yfy United States Patent O 3,359,728 HYDROPNEUMATIC CONTROL DEVICE Edouard Torossian, Bolleystr. 50, Zurich, Switzerland Filed Jan. 7, 1966, Ser. No. 529,902 Claims priority, application Switzerland, Jan. 8, 1965, 259/65 5 Claims. (Cl. 60--54.5)

ABSTRACT F THE DISCLOSURE A pressure multiplying device, for use with a chuck or a vise, having air and liquid under pressure in separate chambers, a pre-tensioned spring to regulate the pressure in the air chamber and a control valve having a valve member which includes two circular grooves, one of which communicates with the air inlet and the o-ther with the air outlet of the air chamber, the control valve being mounted for rotational movement in the end closure of the common housing adjacent the cylinder which separates the air chamber from the liquid chamber and being mounted for perpendicular movement relative to the longitudinal axis of 4the air chamber. Indexing means may be provided to index tension of the pre-tensioned spring.

This invention relates to hydropneumatic control devices more particularly for attachment to bench and other vises for closing and .locking the jaws of the vise. The invention is concerned with a hydropneumatic control device of the kind (hereinafter called the kind referred to) comprising a traction member connected to the movable jaw of the vise and extending through a stationary seat member connected to the other fixed jaw of the vise, the traction member being connected with a cylinder which is slidably mounted in the seat and which forms a compression chamber therewith for hydraulic fluid, the cylinder having a movable wall or piston therein which divides the cylinder into two parts, one part forming a hydraulic reservoir which communicates with the hydraulic compression chamber through an orifice in the end of the cylinder and the other par-t forming a pneumatic chamber containing a pneumatically operable piston, said pneumatic piston having a plunger connected to it and extending through the movable wall or piston for snugly engaging within said orifice and for movement into said hydraulic compression chamber in response to movement of said pneumatic piston.

According to the present invention the closing and locking of the jaws of the vise is carried out by subjecting the pneumatic chamber of the cylinder to air pressure in three distinct and successive steps, namely:

(-a) Compressed air acts on the movable wall or piston so as to force hydraulic fluid from the reservoir through the orifice into the hydraulic compression chamber so as to close the jaws of the vise;

(b) The air pressure on the movable wall or piston is maintained so as to prevent the jaws of the vise ifrom relaxing their grip and compressed air is now directed behind the pneumatic piston which is thereby advanced suiciently in the cylinder so as to engage its plunger within the orifice thus closing the hydraulic compression chamber to stabilise the closing position of the jaws of the vise;

(c) The air pressure is maintained behind the pneumatic piston but the pressure is released from that part of the cylinder between the movable wall and the pneumatic piston which thereby permits the pneumatic piston to move in the cylinder thereby projecting its plunger into the hydraulic compression chamber so as -to produce the necessary high pressure for locking the jaws of the vise.

3,359,728 VPatented Dec. 26, 1967 ice According to the invention these three successive steps of operation of the hydropneumatic control device are attained automatically by the movement of a control valve member in a chamber which has ducts connected with the cylinder for supplying the compressed air thereto, the movement of the valve member being controlled by the air pressure which is being distributed by -the valve, while a compensating spring adjustable as a function of the air pressure is arranged so as to prevent lthe movement of the valve member from one position to another until the step to be performed at each position is absolutely completed.

In order that the invention may be clearly understood the preferred embodiment will now be described with reference to the -accompanying drawings, in which:

FIGURE 1 is a diagrammatic side elevation partly in section of a hydropneumatic control device as attached to a vise;

FIGURE 2 is a longitudinal section through the control device of FIGURE 1;

FIGURE 3 is a plan View of the control device of FIG- URE 2 in which the valve for controlling the supply of compressed -air is shown in section so as to illustrate the details of its constructional features; and

FIGURES 4, 5 and 6 illustrate diagrammatically the different positions of the valve member in the valve housing and which correspond to three distinct steps of operation of the hydropneumatic control device.

Referring now to the drawings and in particular to FIGURE 1 there is shown dia-grammatically by thin lines a bench vise having a stationary jaw I and a movable jaw M. The hydropneumatic device of the invention is drawn with thicker lines and is attached to the back of the vise as shown at the right hand side of FIGURE 1. The hydropneumatic control device is formed with a seat S or stationary part which, as shown, is preferably attached to the xed part of the vise which includes the stationary jaw I.

The traction member of the hydropneumatic control device is shown by the reference P and this extends through the seat S. A tubular member T is pinned or otherwise attached to the traction member P for movement therewith and this tubular element .is provided at one end with a nut portion T1. A conventional threaded member V attached to the manual control of the vise is mounted within the tubular` member T and threadably engages the nut portion T1 so as to -allow the initial coarse adjustment of the jaws of the vise.

After the initial adjustment of the vise by the conventional screw V the hydropneumatic control device of the invention is operated so as to close and then lock the jaws. This operation of the device is obtained by means of a compressed air system whereby compressed air is supplied to the device by the connection 26 as will be hereinafter described. As a result the traction member P is retracted twithin the control device in a direction which is towards the right as viewed in FIGURE l and this movement of the traction member moves also the tubular element T and the movable jaw M so as to rst close the jaws of the vise and then lock them in an automatic and almost instantaneous operation.

The constructional features of the hydropneumatic control device and its air pressure valve are shown in detail in FIGURES 2 and 3 of the drawings and it will be seen rst of all that the traction member P is connected or forms part of a cylinder C which has an end wall F closing the end of the cylinder and which is positioned within the seat member S previously mentioned. The cylinder C and its traction member P are slidably mounted within the yseat S as clearly shown in FIGURE 2 and the seat member is so shaped as to provide a hydraulic compression chamber-7 between the end wall F of the cylinder and the seat member.

A movable wall or piston 1 is positioned in the cylinder C and is normally urged by a spring 2 against a stop member in the form of a circlip 3. The movable wall or piston divides the cylinder C into two parts shown by thereferences Aand B. The part A of the cylinder acts as an expansible reservoir for hydraulic fluid such as oil and this reservoir communicates with the high compres sion chamber 7 through an orifice 4 in the end wall F of the cylinder. As shown, the orifice 4 communicates firstly with a cavity or internal bore 5 in the traction member P and this cavity 5 communicates with the high compression chamber 7 through a number of ports 6.

A pneumatic piston 8 is located in the other part B of the cylinder C and this part of the cylinder forms a pneumatic chamber to which compressed air is supplied as will be hereinafter described. The pneumatic piston 8 is provided with a plunger 9 which is attached thereto for movement with the piston and as shown the plunger 9 slidably passes through the movable wall 1 for movement relatively thereto. As will be hereinafter explained the plunger is movable by the pneumatic piston 8 firstly to engage snugly within the orifice 4 so as to close off, the high compression chamber 7 from the reservoir A, and secondly to project into the cavity 5 to produce the necessary high pressure in the chamber 7.

An end closure member 10 is screwed or otherwise attached to the open end of the cylinder C and this member provides a yoke containing a control valve for controlling the supply of compressed air to the pneumatic chamber or part B of the cylinder C.

The tubular element Tis urged to the left as shown in FIGURE 2 by the spring 13 which seats on the seat member S and this action by the spring 13 tends to move the traction member and the cylinder C to their normal or initial position as shown in FIGURE 2 of the drawlngs.

The supply of air pressure into the chamber B between the movable wall 1 and the piston 8 firstly exerts a pressure on the movable wall 1 so that the wall is moved to the left as shown in FIGURE 2 away from the circlip 3. The movement of the wall 1 forces oil through the orifice 4 into the cavity 5 and so into the chamber 7 through the port 6. The resulting vincrease in the hydraulic pressure in the chamber 7 tends to move the cylinder in the direction of the arrow f as shown in FIGURE 2 away from the stationary seat S. This initial movement of the cylinder C produces a corresponding retraction in the same direction by the tubular element T together with the movable jaw M of the vise so that the jaws of the vise are initially closed and this represents the first step in the operation of the control device of the invention.

The next step in the operation of the Ldevice is the supply of compressed air to the space 11 behind the pneumatic piston at the end of the cylinder. This compressed air is initially supplied without affecting the supply of compressed air to the chamber B in front of the piston 8, but the increase in pressure behind the piston is sufficient to advance it enough to enable the plunger 9 to close the orifice 4 and so cut olf the high compression chamber 7 from the oil reservoir A. This movement thereby stabilises the position of the vise and maintains the closed position of the jaws.

The third step in the operation of the control device is the release of the air pressure in the chamber B or the prooduction of a `reduced pressure therein so as to.

enable the piston 8 to continue its movement towards the movable wall 1 as a result of the air pressure in the space 11 which is, of course, still maintained. As a result the plunger 9 completes its stroke towards the left as viewed in FIGURE 2 yand thus enters the cavity 5 to produce high pressure in the chamber 7 which completes the final step in that the jaws of the vise are now locked firmly in position.

To release the jaws of the vise it is only necessary to produce a reduced pressure or to release the pressure in the space 11 whereby the spring 12 will return the piston 8 to its initial position as shown in FIGURE 2 so that the plunger 9 will withdraw from the cavity 5 and the orifice 4. The combined -action of the springs 2 and 11 causes the oil previously forced into the chamber 7 to return to the reservoir A so that the jaws of the vise are now reopened.

According to the invention the automatic control of the various steps in the clamping operation are obtained by the valve positioned in the end closure member or yoke 10. The construction of this valve is shown in detail in FIGURE 3 of the drawings and it will be seen that the valve includes a slidable valve member 14 which moves in a chamber 15 along an axis which is at right angles to the longitudinal axis of the cylinder C. The Valve member 14 is a cylindrical member and is formed with two circular channels or grooves 16 and 17 which are isolated from each other and from the corresponding ends of the valve member by sealing devices 18 whose width and spacing are carefully selected. The valve member also has two longitudinal bores 19 and 20 as shown in FIGURE 4 and which communicate one with each end of the valve member. As shown, the longitudinal bore 19 communicates with that end of the valve member 14 which faces the compressed air inlet connection 26 while the longitudinal bore faces the outlet end of the chamber 15 and which communicates with atmosphere through an orifice in end closure plug 27. The bore 19 also communicates with the circular groove 16 while the bore 20 also cornmunicates with the circular groove 17.

Two ducts or ports 21 and 22 are provided in the wall of the chamber 15 of the valve so as to communicate with the pneumatic chamber of the cylinder C. The duct 21 leads into a fixed tube 23 which extends into an axial cavity 24 in the centre of the plunger 9. The wall of the plunger is provided with ports 25 so that compressed air can be supplied to the chamber B on that side of the piston 8 adjacent the movable wall 1. Duct 22 passes through the wall of the closure member 10 and communicates directly with the space 11 behind the piston 8.

The threaded closure plug 27 is formed with an internal bore providing a seat for a spring 28 the tension of which can be varied to allow the movement of the valve member 14 as a function of the compressed air pressure supply. The plug 27 has a threaded skirt portion 29 which threadably engages the wall of the chamber 15 and the tightness of which can be varied by slightly separating a milled cross portion 30. In addition, the plug has a smooth portion 31 with milled markings 32 and a knurled flange 33 as shown particularly in FIGURE 3.

The movement of the valve member from its initial position as shown in FIGURE 4 to its final position as shown in FIGURE 6 is limited by -a circlip 34 mounted in the wall of the chamber 15.

FIGURES 4, 5 and 6 show the three main positions or steps in the movement of the valve member 14 in its chamber 15 and these positions correspond to the three steps in the operation of the hydropneumatic control device of the invention.

Referring now to FIGURE 4 the air supply connection 26 is initially open to atmosphere but the connection is controlled by a multiway valve under the control of an operator either manually or by a foot pedal. When the valve is operated the connection 26 is closed to atmosphere and is connected to the supply of compressed air.

Initially the valve member 14 is acted on only by the spring 28 and is, therefore, in its initial position at the end of the chamber 15 as shown in FIGURE 4. In this position the circular groove 16 is in communication with a duct 21 so that the chamber B is also connected to atmosphere while the space 11 is connected to atmosphere through the duct 22 and the port in the closure plug 27.

As compressed air is supplied through the connection 26 this will pass into the circular groove 16 and it is to be noted that this groove is Wider than the distance between the ducts or ports 21 and 22 so that some time during the movement of the valve member 14 both ducts will be connected for a moment with the air pressure supply.

The operation of the hydropneumatic control device will now be described with reference to hypothetical values which have been chosen merely by way of example.

It may be assumed that the cross sectional area on the sealing device 18 is 3 square centimeters and that the compressed air supply is at a pressure of atmospheres. When the manual valve is operated to connect the connection 26 to the air pressure supply the compressed air passes into the bore 19 with some reduction in pressure and then into the groove 16 and thereby into the chamber B so as to move the wall 1. At this time the pressure of the air supply also acts to some extent on the end of the valve member 14 and thereby forces it to move in its chamber towards the right against the action of the spring 28. This movement is, of course, resisted by the spring 28 otherwise the valve member would immediately complete its stroke against the circlip 34 so that the channel 16 would immediately become connected with the duct 22 to actuate the plunger 9 before the jaws of the vise had time to properly close.

If, on the other hand, the spring 28 is adjusted so as to provide an opposite force on the valve member which is greater than 15 kg. the compressed air after causing the jaws of the vise to close and thus stabilise itself at the initial pressure of 5 atmospheres would, in fact, be unable to move the valve member any further because its maximum pressure on the valve member could not exceed 3 5=15 kg. The plunger 9 would not, therefore, work to provide the necessary high compression and the vise would be closed but not locked. This is why it is necessary to control the tension of the spring 28 carefully as a function of the incoming air pressure.

In the present calculations it can, therefore, be assumed that the spring 28 is adjusted to exert on the valve member a pressure of 9 kg. when the valve member is in the position shown in FIGURE 4 and a pressure of 12 kg. in the position shown in FIGURE 6. The compressed air entering the connection 26 at a pressure of 5 atmospheres is momentarily expanded by its passage into the chamber B and will reach 3 kg. before it moves the valve member which is sufficient to cause closing `of the jaws of the vise. When this pressure has 4been passed the valve member will increase its movement thus passing into the intermediate position shown in FIGURE 5 in which the action of the compressed air is applied to the piston 8 while the pressure in the chamber B is maintained by cutting off the duct 21. Then, since the air pressure tends to stabilise itself at 5 kg. on the piston 8 its action on the valve member 14 will finally exceed the 12 kg. exerted by the spring 28 and the valve member will finally engage the circlip 34 to reach its final position as shown in FIG- URE 6. In this position the circular groove 17 is now opposite the duct 21 and this causes the pressure to be reduced in the chamber B as the chamber is now connected with atmosphere through the port in the plug 27. The Piston 8 can now move fully to enable the plunger 9 to effect locking of the jaws by the production of the high compression in the chamber 7.

The jaws of the vise are opened by simply closing the air inlet valve in the connection 2,6. The connection 26 is thereby connected to atmosphere and the valve member 14 will lreturn to its initial position as shown in FIG- URE 4 under the action of the spring 28.

What I claim is:

1. An aerohydraulic pressure control device for attachment to a vise which first closes and then locks the jaws of the vise comprising:

(a) a cylinder having a cup shaped head;

(b) a spring-urged piston in'said cylinder which normally bears in a forward direction against said head by the force of said spring;

(c) said piston having an axially mounted plunger and a movable wall portion which is in `stepped conformation adapted to the cup shape of said cylinder head and which divides the cylinder into a first chamber in advance of said wall defining an expansible reservoir for hydraulic fluid confined between the piston wall and cylinder head and a second charnber behind said wall for compressed air adapted to drive said piston wall forward;

(d) an end closure for the end of said cylinder which is remote from the cylinder head, said end closure defining a longitudinal chamber arranged as a central continuation of the cylinder with the axis of the chamber being perpendicular to the axis of the cylinder, said end closure being yfurther fitted with inlet openings for compressed air which feed either into the second chamber or into the space behind the piston in said cylinder;

(e) a control valve mounted in said longitudinal chamber which is movable either in closing alignment with the inlet into said second chamber or in closing alignment with the inlet into said space behind the piston in said cylinder, said control valve being formed with annular grooves;

(f) a longitudinal bore forming an air passageway in said valve member which communicates with said second chamber, the forward wall of said valve member opening the air inlet to admit compressed air into said second chamber; and,

(g) a pre-tensioned spring attached to said control Valve which urges said control valve against closing of the air inlet t0 thereby maintain a predetermined -air pressure into said second chamber whereby the forward pressing movement of said piston is assured by the hydraulic liquid pressure until the jaws are locked.

2. An aerohydraulic pressure control device as claimed in claim 1, wherein said cylinder is provided with a ring mounted adjacent the cylinder head, said -ring serving as a stop against the forward motion of the wall portion of said piston.

3. A control device as claimed in claim 1, wherein said control valve is cylindrical, one of said grooves communicates with the air inlet and said valve includes a housing portion having an air outlet which communicates with the other of said grooves.

4. A control device as claimed in claim 3, wherein said valve is fitted with an adjustable plug to adjust the tension of the pre-tensioned spring and said plug includes a cylindrical sleeve which is connected to said end closure portion, said sleeve having means to index its rotational movement to adjust the tension of said plug.

5. A control device las claimed in claim 3, wherein said device is furnished with a seat member adapted to be attached to the fixed part of the vise.

References Cited UNITED STATES PATENTS 10/ 1965 Torossian. 

1. AN AEROHYDRAULIC PRESSURE CONTROL DEVICE FOR ATTACHMENT TO A WISE WHICH FIRST CLOSES AND THEN LOCKS THE JAWS OF THE VISE COMPRISING: (A) A CYLINDER HAVING A CUP SHAPED HEAD; (B) A SPRING-URGED PISTON IN SAID CYLINDER WHICH NORMALLY BEARS IN A FORWARD DIRECTION AGAINST SAID HEAD BY THE FORCE OF SAID SPRING; (C) SAID PISTON HAVING AN AXIALLY MOUNTED PLUNGER AND A MOVABLE WALL PORTION WHICH IS IN STEPPED CONFORMATION ADAPTED TO THE CUP SHAPE OF SAID CYLINDER HEAD AND WHICH DIVIDES THE CYLINDER INTO A FIRST CHAMBER IN ADVANCE OF SAID WALL DEFINING AN EXPANSIBLE RESERVOIR FOR HYDRAULIC FLUID CONFINED BETWEEN THE PISTON WALL AND CYLINDER HEAD AND A SECOND CHAMBER BEHIND SAID WALL FOR COMPRESSED AIR ADAPTED TO DRIVE SAID PISTON WALL FORWARD; (D) AN END CLOSURE FOR THE END OF SAID CYLINDER WHICH IS REMOTE FROM THE CYLINDER HEAD, SAID END CLOSURE DEFINING A LONGITUDINAL CHAMBER ARRANGED AS A CENTRAL CONTINUATION OF THE CYLINDER WITH THE AXIS OF THE CHAMBER BEING PERPENDICULAR TO THE AXIS OF THE CYLINDER, SAID END CLOSURE BEING FURTHER FITTED WITH INLET OPENINGS FOR COMPRESSED AIR WHICH FEED EITHER INTO THE SECOND CHAMBER OR INTO THE SPACE BEHIND THE PISTON IN SAID CHAMBER; (E) A CONTROL VALVE MOUNTED IN SAID LONGITUDINAL CHAMBER WHICH IS MOVABLE EITHER IN CLOSING ALIGNMENT WITH THE INLET INTO SAID SECOND CHAMBER OR IN CLOSING ALIGNMENT WITH THE INLET INTO SAID SPACE BEHIND THE PISTON IN SAID CYLINDER, SAID CONTROL VALVE BEING FORMED WITH ANNULAR GROOVES; (F) A LONGITUDINAL BORE FORMING AN AIR PASSAGEWAY IN SAID VALVE MEMBER WHICH COMMUNICATES WITH SAID SECOND CHAMBER, THE FORWARD WALL OF SAID VALVE MEMBER OPENING THE AIR INLET TO ADMIT COMPRESSED AIR INTO SAID SECOND CHAMBER; AND (G) A PRE-TENSIONED SPRING ATTACHED TO SAID CONTROL VALVE WHICH URES SAID CONTROL VALVE AGAINST CLOSING OF THE AIR INLET TO THEREBY MAINTAIN A PREDETERMINED AIR PRESSURE INTO SAID SECOND CHAMBER WHEREBY THE FORWARD PRESSING MOVEMENT OF SAID PISTON IS ASSURED BY THE HYDRAULIC LIQUID PRESSURE UNTIL THE JAWS ARE LOCKED. 